1. Field of the Invention
The present invention relates to an IC socket having a plurality of contact pins for connecting terminals of an integrated circuit (IC) and an external circuit board for the purpose of conducting an electric test for the IC.
2. Description of the Related Art
As shown in FIG. 13, an IC socket 100 of an open top type has a plurality of contact pins 101 attached to a socket body 102 for connecting terminals 111 of an IC (e.g. QFP, SOP, TSOP) 110 (see FIG. 14) and an external electric testing circuit (not shown). Each contact pin 101 comprises a movable pin 105 and a stationary pin 107. A cover 104 having an IC loading window 103 is supported by the socket body 102 so as to be vertically movable in FIG. 13.
When the cover 104 is pushed downward in FIG. 13, the movable pins 105 are pushed by the cover 104 to be bent so that movable contact portions 106 of the movable pins 105 retreat from stationary contact portions 108 of the corresponding stationary pins 107 to receive the corresponding IC terminals 111 on the stationary contact portions 108. Then, when the cover 104 returns to the initial position, each of the IC terminals 111 is pressed against the stationary contact portion 108 due to an elastic force of the movable pin 105 so as to be firmly held between the movable contact portion 106 and the stationary contact portion 108 (see FIG. 14). In this state, the IC terminals 111 are energized to conduct an electric test for the IC 110.
As best seen in FIG. 14, each stationary contact portion 108 is increased in size as compared with the other portions of the stationary pin 107 for stably receiving the IC terminal 111 thereon, while the socket body 102 is recessed for ensuring a sufficient space for each of the enlarged stationary contact portions 108.
After the electric test for the IC 110 has been finished, the cover 104 is again pushed downward in FIG. 13 to retreat the movable contact portions 106 from the stationary contact portions 108 so that the IC 110 is removed from the IC socket 100.
In the foregoing conventional IC socket 100, each of the contact pins 101 is mounted to the socket body 102 such that the corresponding stationary pin 107 is forcibly displaced from a dotted line position to a solid line position as shown in FIG. 13, so as to support the corresponding IC terminal 111 on the stationary contact portion 108. However, as seen from FIGS. 13 and 14, no means are provided for positioning the stationary contact portions 108 in vertical directions in the figures. Thus, it is possible that manufacturing errors of the contact pins 101 and/or assembling errors thereof relative to the socket body 102 cause supporting positions of the IC terminals 111 to be largely dispersed among the contact pins 101.
In such a case, if the IC terminals 111 are made of a relatively soft material such as copper, they may be deformed when sandwiched between the stationary contact portions 108 and the movable contact portions 106.
Therefore, it is an object of the present invention to provide an IC socket which is capable of improving accuracy of supporting positions of IC terminals and thus avoiding deformation of the IC terminals.
It is another object of the present invention to provide contact pins for use in such an IC socket.
According to one aspect of the present invention, there is provided an IC socket comprising a socket body elastically supporting a cover having an IC loading window, the cover being movable toward and away from the socket body; and a plurality of contact pins attached to the socket body for connecting IC terminals and an external electric testing circuit, each of the contact pins comprising: a base portion fixed to the socket body; a first contact portion connected to the base portion via a first spring portion for supporting corresponding one of the IC terminals; and a second contact portion connected to the base portion via a second spring portion, the second contact portion forced by the cover, when the cover is moved toward the socket body, so as to elastically deform the second spring portion so that the second contact portion retreats from the first contact portion to allow the one of the IC terminals to be received on the first contact portion, and the second contact portion pressing the one of the IC terminals against the first contact portion by means of an elastic force of the second spring portion when the cover returns to an initial position, wherein each of the first contact portions is formed with a positioning stepped portion, and the socket body is formed with a positioning engaging portion which engages with the positioning stepped portion in a state where the first spring portion is elastically deformed, so that the positioning stepped portion is pressed against the positioning engaging portion by means of an elastic force of the first spring portion.
It may be arranged that the positioning stepped portion is pressed against an upper surface of the positioning engaging portion by means of a tensile force of the first spring portion.
It may be arranged that the positioning stepped portion is pressed against a lower surface of the positioning engaging portion by means of a compressive force of the first spring portion.
It may be arranged that the positioning stepped portion is in the form of one of a projection and a recess, and the positioning engaging portion is in the form of one of a recess and a projection, which are engaged with each other.
It may be arranged that contact surfaces of the positioning stepped portion and the positioning engaging portion are inclined surfaces.
It may be arranged that the positioning engaging portion is detachably mounted to the socket body.
According to another aspect of the present invention, for use in an IC socket having a plurality of contact pins attached to a socket body for connecting IC terminals and an external electric testing circuit, the socket body elastically supporting a cover having an IC loading window and movable toward and away from the socket body, each of the contact pins comprising a base portion fixed to the socket body; a first contact portion connected to the base portion via a first spring portion for supporting corresponding one of the IC terminals; and a second contact portion connected to the base portion via a second spring portion, the second contact portion forced by the cover, when the cover is moved toward the socket body, so as to elastically deform the second spring portion so that the second contact portion retreats from the first contact portion to allow the one of the IC terminals to be received on the first contact portion, and the second contact portion pressing the one of the IC terminals against the first contact portion by means of an elastic force of the second spring portion when the cover returns to an initial position, wherein each of the first contact portions is formed with a positioning stepped portion which engages with a positioning engaging portion formed at the socket body in a state where the first spring portion is elastically deformed, so that the positioning stepped portion is pressed against the positioning engaging portion by means of an elastic force of the first spring portion.